The conventional sewing of a flap with a rough closing edge on a fabric part with a pocket placed on in advance is carried out, as is shown in FIGS. 4 and 5, in two partial steps. In a first partial step, the flap 10 with its rough closing edge 14, being in a rotated position in relation to the finished position of use 11, is aligned at a predetermined distance from the sewn-on pocket 9, taking into account the course of the pattern 17 of the fabric part, pocket and flap, and is connected to the fabric part 6 by means of a fastening seam 12. The flap 10 is then rotated by 180.degree. into its position of use 11 around this fastening seam 12 in the second partial step and is connected to the fabric part 6 with a cover seam (top seam) 13, and the distance 15 between the cover seam 13 and the fastening seam 12 is selected to be such that the rough closing edge 14 of the flap 11 placed on in the finished position is no longer visible. This operation, which is carried out freely guided by hand, requires a high skill on the part of the seamstress to maintain the specified position of the flap 11 in relation to the pocket 9 and also to make the course 17 of the stripes or checks to be congruent within the specified tolerances in the case of figured fabrics. The process used here is extraordinarily time-consuming and requires a very large amount of training in order to meet the quality specifications and the required output.
A process and an automatic sewing machine for sewing a flap on a fabric part, in which the flap has a folded (clean) closing edge, is described in the patent DE 41 24 164 C2. In this case, the flap is pre-positioned in an offset parking position in relation to the pocket and is displaced into the position of use proper after the pocket has been sewn on, and is then sewn on. This process is not suitable for sewing on a flap with a rough closing edge for quality reasons, because the rough closing edge is visible after the flap has been sewn on.